Eating cured and processed meat, such as ham and salami, can worsen asthma.
Four or more weekly servings — considered to be a high amount — exacerbate symptoms the most, according to the journal, Thorax.
Cured and processed meat is rich in nitrites, which may inflame airways, a typical feature of asthma.
To find out if dietary processed meat intake was associated with the worsening of asthma, and what role, if any, obesity might have, the researchers drew on data from participants in a French epidemiological study on the genetics and environment of asthma (EGEA).
It tracked the health, through surveys and medical examination, of 2,000 asthma patients, their relatives, and a comparison group from five cities in France for 20 years.
The current study is based on 971 adults, for whom complete dietary, weight (BMI), asthma-symptom score, and demographic data were obtained up until 2011 to 2013.
Dietary intake was measured using food frequency questionnaires encompassing 118 items in 46 food groups. Cured meat intake — ham, sausage, salami — was classified as low for one or fewer weekly servings, medium for one to four weekly servings, and high for four or more.
Asthma symptoms, such as difficulty breathing, chest tightness, and shortness of breath in the preceding 12 months, were scored from zero to five (asthma symptom score).
Information was also gathered on other potentially influential factors, such as smoking, regular physical activity, age, sex, and educational attainment.
Among those who ate one or fewer weekly servings, the proportion of those with worsening asthma symptoms was 14%.
Among those eating one to four, the proportion was 20%, and among those eating four or more, the proportion was 22%.
After taking account of potentially influential factors, such as smoking, regular physical activity, age, sex, and educational attainment, those who ate the most cured meats were 76% more likely to experience worsening asthma symptoms than those who ate the least.
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